Random Stat: Team Quarter by Quarter results

Q: was wondering if you've ever looked at the relationship between a team's
record in individual quarters and how that relates to their overall record.
obviously teams that win more quarters will win more games, but i'm thinking
about it in the same way run differential is used in baseball to predict
which teams are under-performing and due for a winning streak and those that
are over-performing and due, say, to fall in the season's second half?
-- Aaron Wherry

A: Good idea, let's take a look!

Team Quarter by Quarter to 2/22

2005-06

YTD

Winning% by Quarter

OT

CBA

Team

W-L

1st

2nd

3rd

4th

W-L

Pts

Detroit

43-9

.640

.553

.673

.531

2-2

252.5

Dallas

42-11

.647

.580

.558

.600

4-2

251.5

San Antonio

41-12

.686

.592

.620

.500

3-2

249

Phoenix

36-17

.673

.617

.569

.580

1-4

236

Miami

34-20

.549

.511

.560

.577

2-0

220

Cleveland

32-22

.529

.551

.571

.521

3-0

212.5

Memphis

30-23

.538

.608

.627

.469

1-3

208.5

L.A. Clippers

30-23

.490

.500

.694

.560

3-2

208

New Jersey

30-23

.540

.490

.580

.529

2-0

203

Denver

29-26

.462

.520

.577

.519

2-4

201

New Orleans

29-25

.500

.569

.407

.549

0-2

196

Indiana

27-23

.490

.659

.531

.580

0-0

193

L.A. Lakers

27-26

.592

.543

.460

.500

3-3

191.5

Washington

27-25

.521

.469

.542

.481

3-1

185.5

Sacramento

25-29

.519

.519

.490

.440

3-3

181.5

Utah

26-28

.462

.400

.500

.510

4-2

179.5

Chicago

24-29

.549

.353

.520

.571

2-5

177.5

Golden State

24-29

.440

.490

.608

.440

1-2

177

Minnesota

23-30

.583

.412

.520

.531

0-3

177

Philadelphia

26-27

.538

.531

.347

.442

4-3

177

Milwaukee

27-27

.440

.365

.529

.353

4-1

173

Houston

23-31

.380

.490

.462

.577

2-1

172.5

Boston

21-33

.423

.413

.509

.500

1-3

163.5

Toronto

20-34

.408

.510

.449

.538

1-4

163.5

Seattle

21-34

.462

.462

.265

.385

3-2

151.5

Orlando

19-34

.412

.529

.400

.392

2-3

149.5

Portland

18-35

.431

.447

.347

.408

1-1

142

Atlanta

16-36

.380

.500

.471

.404

1-1

139.5

Charlotte

15-41

.365

.444

.339

.529

3-2

139.5

New York

15-38

.347

.412

.286

.490

3-3

128

Fans of the old CBA may remember at one point their standings counted quarter scores as well as the final result:

3 pts for a win
1 pt for each quarter won
1/2 pt for a tied quarter

So the table shows the winning percentage for each team by quarter -- note that we ignore "tied quarters" so Detroit is 32-18-2 in the first quarter, which we score as a .640 success rate.

Correlations for winning % in a quarter to overall win rate?

.86 - 1st Qtr
.56 - 2nd Qtr
.71 - 3rd Qtr
.44 - 4th Qtr

That first quarter number is powerful indeed, which makes you wonder about teams like Minnesota (.583 Q1) and Chicago (.549) while raising doubts about the Nuggets (.462) and Clippers (.490)

For those big on halftime speeches though, Dunleavy's Clips are the #1 team for 3rd Qtr win rate at .694

The Sixers meanwhile have excellent first half results, but fall apart completely in the third quarter and limp home in the fourth.

Now you may be wondering what the game by game correlation is for winning a quarter and winning the game, and that works out to be:

.37 - 1st Qtr
.29 - 2nd Qtr
.40 - 3rd Qtr
.28 - 4th Qtr

So on a single game basis, the third quarter has been the most predictive, edging out the first quarter.

Of course counting a one point lead the same as a twelve point lead has its drawbacks, so let's look at the net points per quarter by team for another take on matters.

Team Qtr by Qtr to 2/22

2005-06

YTD

Net Points by Quarter

Team

W-L

Game

1st

2nd

3rd

4th

OT

Detroit

43-9

+8.5

+2.8

+1.8

+3.5

+0.4

-1.0

Dallas

42-11

+7.2

+2.9

+1.2

+0.6

+2.1

+2.2

Phoenix

36-17

+6.8

+3.0

+2.7

+1.2

+0.1

-1.2

San Antonio

41-12

+6.5

+2.9

+1.1

+2.6

-0.4

+3.8

Miami

34-20

+4.1

+1.2

-0.1

+1.6

+1.1

+5.0

Indiana

27-23

+3.2

+0.2

+1.1

+1.3

+0.6

+0.0

Cleveland

32-22

+3.0

+0.0

+1.3

+0.9

+0.5

+6.3

Memphis

30-23

+2.3

+0.0

+2.3

+0.9

-0.8

-1.8

L.A. Clippers

30-23

+1.4

-0.2

-1.0

+2.0

+0.8

-0.6

L.A. Lakers

27-26

+1.4

+1.0

+0.0

+0.0

+0.6

-1.5

Washington

27-25

+1.4

+0.8

-0.6

+0.5

+0.3

+4.8

Denver

29-26

+0.6

-0.5

+0.4

-0.1

+0.9

-1.0

New Jersey

30-23

+0.5

+0.5

-0.1

+0.2

-0.4

+7.5

Sacramento

25-29

+0.5

+0.4

+0.4

+0.8

-1.3

+1.3

Chicago

24-29

-0.1

+1.3

-1.7

+0.4

+0.3

-2.7

Golden State

24-29

-0.4

-1.3

-0.6

+2.1

-0.5

-1.3

New Orleans

29-25

-0.7

-0.7

+1.7

-1.7

+0.2

-5.0

Minnesota

23-30

-1.0

+1.6

-1.2

-0.8

-0.5

-2.3

Houston

23-31

-1.1

-2.1

+0.3

-0.3

+1.0

+0.7

Philadelphia

26-27

-1.6

+0.1

+0.5

-1.4

-0.6

-1.1

Boston

21-33

-1.7

-0.8

-0.9

+0.1

-0.2

+1.8

Milwaukee

27-27

-1.8

-0.5

-1.2

+1.0

-1.4

+2.8

Toronto

20-34

-2.3

-1.3

-0.3

-1.5

+1.2

-4.2

Utah

26-28

-3.0

-0.7

-1.5

-1.6

+0.8

+0.0

Orlando

19-34

-3.3

-1.1

-0.8

-1.1

-0.2

-2.0

Charlotte

15-41

-4.8

-1.8

-0.3

-3.0

+0.1

+0.4

Seattle

21-34

-5.1

-0.6

-0.4

-2.3

-1.9

+0.4

Atlanta

16-36

-5.7

-2.3

-1.5

-0.3

-1.5

-2.5

New York

15-38

-6.0

-2.2

-1.5

-2.6

+0.4

-1.3

Portland

18-35

-7.8

-2.3

-1.0

-2.6

-1.8

-1.5

The point differential (net points per game) is generally a better playoff predictor than pure win% and you can see right now there are four powerhouse teams in the NBA.

Running the correlations for net points per quarter to overall winning percentage shows:

.85 - 1st Qtr
.67 - 2nd Qtr
.75 - 3rd Qtr
.38 - 4th Qtr

This again reinforces the 1st/3rd quarters as key, with the fourth quarter less important because of the number of "decided" games having to be played out.

So the oft spouted concept that NBA games are just back and forth and it all comes down to the last few minutes when the superior teams exert their will is demonstrably false: the good teams get the lead early and hold on.

If you just add the net points for the 1st quarter and 3rd quarter together, you get:

1) Detroit +6.3
2) San Antonio +5.5
Hmmm...

Getting back to the second part of Aaron's question though, what teams might we predict for better/worse performance in the post All Star break part of the season? That's something that really requires more research since if a team shows inconsistent results from one quarter to another, which quarter is the aberration?

Still, if you do a quick regression on the net points numbers, you get an R^2 of .88 with this:

So plugging in the numbers we find these are the outlier teams (actual win% minus projected win% listed alongside the team name, so Utah have an actual win% of .481 but a projected by the qtr net points of .390, meaning they have won +.091 more than would be expected from their quarter splits):

Over-achievers

Utah +.091

Portland +.081

Dallas +.072

Milwaukee +.060

New Orleans +.055

New Jersey +.051

San Antonio +.049

Detroit +.041

L.A. Clippers +.034

Seattle +.025

Underachievers

Phoenix (!) -.073

Sacramento -.064

Chicago -.062

Charlotte -.062

Minnesota -060

Indiana -.054

Boston -.046

Toronto -.046

L.A. Lakers -.045

Orlando -.033

If the Suns are truly under-achieving then the rest of the league better watch out! On the other hand we wouldn't be surprised if the Kings and Pacers looked much better in the remaining games, now that the Artest/Peja situation has been settled.

For the over-achievers the key is perhaps the teams without much margin of error in making the playoffs -- could Milwaukee and New Orleans slip out of the top eight in their respective conferences?

Do you have an idea for a cool "random stat" you would like to see? If so, drop us a line